Human hair is made up of proteins, and the structure and modeling thereof are guaranteed by disulfide bridges between the amino acids of the polypeptide chain. These bridges are covalent bonds that may be disrupted in extreme pH conditions. From the disruption of these bonds it is then possible to shape the hair strand as desired (straighten or curl).
The disruption of disulfide bridges can be carried out with substances that modify the pH in an extreme way, such as, for example, hydroxides. However, the use of such substances leaves the hair dehydrated, with open scales, thus, in need of a conditioning agent to restore its normal structure.
In this sense, there is a constant search for cosmetic compositions which are capable of shaping or straightening keratinous fibers, particularly the hair, but without damaging the strands, which are atoxic, of easy application and maintenance.
Eucalyptus ashes contain alkaline and alkaline earth minerals in the presence of carbonates that, when in solution, ensure the property of keeping the pH high. This solution, when applied to the hair strand, acts by disrupting the disulfide bonds, thus enabling the realization of a new hair modeling.
It is known in the prior art that only these ashes in solution are able to shape the hair, however, at the same time they are aggressive to the hair strand, rendering it weak, opaque and brittle.
Currently, modeling or straightening procedures of keratinous fibers are carried out by the use of plasticizer products, natural and synthetic resins, as well as formaldehyde, cysteine and other derivatives of sulfur, in addition to glutaraldehyde, hydrogen peroxide, ammonium thioglycolate, quaternary ammonium compounds and pH altering substances, all applied in isolation or through combinations among them.
Most commonly used products are products based on formaldehyde (formalin), which is a chemical compound capable of altering the structure of the hair strand. However, its use is restricted due to the fact that it is a carcinogenic compound. In addition, its application requires caution so that it does not harm the hair strand, the scalp, or the health of the human being.
Thus, the present invention aims to solve the problems mentioned above, providing a new cosmetic composition for straightening or modeling keratinous fibers, particularly the hair, which does not present the drawbacks found in the prior art.